Can discharge unit and can forming machine

ABSTRACT

Provided are a can discharge unit and a can forming machine including a can body holder in which the can body does not fall at an unexpected timing. 
     A knockout unit has a knocking out piston which is disposed to be movable in a depth direction of a cylindrical part and is provided to be displaceable between a protruding position at which the knocking out piston protrudes into the cylindrical part and a recessed position at which the knocking out piston exits the cylindrical part, and a cylinder which supports the knocking out piston to be displaceable. At a discharge position at which the formed can body is discharged from the cylindrical part of the can body holder, a piston displacing unit which displaces the knocking out piston from the recessed position toward the protruding position is provided adjacent to the other surface side of the base.

BACKGROUND OF THE INVENTION

Priority is claimed on Japanese Patent Application No. 2016-106552, filed May 27, 2016 and Japanese Patent Application No. 2017-100768, file May 22, 2017, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a can discharge unit and a holding unit of a can body in a can forming machine.

BACKGROUND OF THE INVENTION

As a can body that is filled with contents such as a beverage and sealed, a bottomed cylindrical can body having a can barrel (wall) and a can bottom (bottom), and a bottle can with a thread cap screwed onto an opening end portion of the can are known. The can body of such a bottle can is diagonally narrowed so that an upper portion is constricted, and a thread groove for screwing the thread cap is formed on the side of the opening portion.

When such a bottle can is formed, for example, a product (a can base material) obtained by drawing a metal plate made of aluminum or an aluminum alloy into a cup shape is redrawn using the can forming machine, and the side walls are stretched in multiple ironing steps. After adjusting the height of the can body thus obtained by trimming, printing is performed on a circumferential surface of the can body. Thereafter, a bottle can is formed through a necking process in which the opening end side of the can body is drawn.

In the forming of such a bottle can, the bottle necker, which is a can forming machine used in the necking process, rotates a turntable in which multiple can body holders for supporting the bottom side of the can body are arranged in an annular shape. Further, in order to face the respective can body holders, opening end sides of the can body held by the can body holder are sequentially pressed against multiple necking toolings arranged on the die table in a ring shape, and drawing is performed in steps (see, for example, Japanese Unexamined Patent Application, First Publication No. 2008-126266).

In a slide air valve unit described in Japanese Unexamined Patent Application, First Publication No. 2008-126266, in order to supply gas for detaching a can body to a rotating can body holder, a fixing member including multiple long grooves through which gas flows is provided. By moving one end of a gas supply pipe extending from each of the can body holders along the long groove with the rotation of the can body holder, even if the can body holder rotates, it is possible to supply the gas.

Conventionally, as a unit for holding a can body in a bottle necker or the like, for example, there is a container holder described in Japanese Unexamined Patent Application, First Publication No. 2008-126266. The container holder includes a container holding member which expands with the supply of air to hold the circumferential surface of the container, and a piston which pushes out the container from the holder.

The slide air valve unit disclosed in Japanese Unexamined Patent Application, First Publication No. 2008-126266 is configured so that an air pipe which operates a container holding member for holding a container, and an air pipe which operates the piston for pushing out the container are always connected to each other via a manifold while the holder rotates. For this reason, there was a risk of the piston unexpectedly operating due to an erroneous operation of a valve or the like for controlling the supply of air, and the container being pushed out and falling when the holder was not at a container extraction position.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a can discharge unit and a can forming machine in which a can body does not fall from a can body holder at an unexpected timing.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, according to an aspect of the present invention, there is provided a can discharge unit including: a cylindrical part into which a can body can be inserted; a knocking out piston which is disposed to be movable in a depth direction of the cylindrical part and is provided to be displaceable between a protruding position and a recessed position; and a piston displacing unit which displaces the knocking out piston from the recessed position toward the protruding position, wherein the piston displacing unit is disposed selectively to a discharge position where the can body is discharged from the cylindrical part.

In addition, according to other aspect of the present invention, there is provided a can forming machine which includes a turntable in which multiple can body holders configured to detachably hold a can body are annularly arranged on one surface side (the first surface side) of a base in a disc shape, the can body holders have a cylindrical part into which at least a bottom side of the can body can be inserted, and a knockout unit, the knockout unit has a knocking out piston which is disposed to be movable in a depth direction of the cylindrical part and is provided to be displaceable between a protruding position at which the knocking out piston protrudes into the cylindrical part and an recessed position at which the knocking out piston exits the cylindrical part, and a cylinder which supports the knocking out piston to be displaceable, and at a discharge position at which the formed can body is discharged from the cylindrical part of the can body holders, a piston displacing unit which displaces the knocking out piston from the recessed position toward the protruding position is provided adjacent to the other surface (the second surface side) side of the base.

According to the can forming machine of the present invention, since the piston displacing unit for operating the knocking out piston is disposed at least to the position at which the can body is discharged from the can body holding unit, it is possible to reliably prevent an erroneous operation in which the knocking out piston unexpectedly protrudes into the cylindrical part during machining of the can body and causes the can body being machined to fall.

An opening through which one surface side (the first surface side) and the other surface side (the second surface side) of the base communicate with each other may be formed in a part of the base in which the can body holders are disposed.

The piston displacing unit may be a gas valve connected to a gas pressure adjusting unit which feeds gas into the cylinder.

The gas valve may be further disposed to one or more positions between a position subsequent to the discharge position to the introduction position along a rotational direction of the turntable, and may not be disposed between the position subsequent to the introduction position and a position previous to the discharge position.

The gas valve may be disposed to each position between the discharge position and an introduction position at which the can body before forming is introduced into the cylindrical part, and the gas pressure adjusting unit may feed gas into the cylinder via the gas valve and suction the interior of the cylinder to displace the knocking out piston from the protruding position toward the recessed position.

Other aspect of the present invention is a can body holder including: a cylindrical part which receives a lower portion of a can body; a can body holding unit disposed to an inner circumferential surface side of the cylindrical part; and a knockout unit disposed to a bottom surface side of the cylindrical part, wherein the can body holding unit includes an elastic part partially exposed on the inner circumferential surface of the cylindrical part, and the knockout unit includes a knockout cylinder, and a knocking out piston supported inside the knockout cylinder to be movable in an axis direction of the knockout cylinder.

In the can body holder of the other aspect of the present invention, the elastic part may be in a ring shape having a rectangular cross section, made of rubber, a hollow portion may be formed in the rectangular cross section, and a first gas pressure adjusting unit configured to apply a gas pressure from outside to an inside of the hollow portion may be connected to the elastic part.

In addition, in the can body holder of the other aspect of the present invention, a substantially cylindrical cylinder shape may be formed in the knockout cylinder, a pressure adjusting hole may be disposed to the knockout cylinder to release an air compressed in the knockout cylinder by movement of the knocking out piston.

According to the present invention, it is possible to provide a can discharge unit and a can forming machine in which the can body does not fall from the can body holder at an unexpected timing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating forming processes of a DI can in stages.

FIGS. 2A-2G are schematic views illustrating change in shapes of can bodies in each process.

FIG. 3 is an external perspective view illustrating a can forming machine (necking apparatus) including a can discharge unit.

FIG. 4 is a perspective view illustrating a turntable and its vicinity.

FIG. 5 is an enlarged perspective view illustrating a main part of the turntable.

FIG. 6 is a plan view of the turntable seen from the die table side.

FIG. 7 is a partially broken perspective view illustrating a configuration of a can body holder.

FIG. 8 is a cross-sectional view illustrating a configuration of the can body holder.

FIG. 9 is an enlarged perspective view of a main part when the vicinity of a can body insertion position of the turntable is viewed from the back side.

FIG. 10 is a partially broken perspective view when the vicinity of the can body discharge position of the turntable is viewed from the front surface side.

FIG. 11A-11B is cross-sectional views illustrating the operation of a can body holding unit.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a can forming machine including a can discharge unit of an embodiment of the present invention will be described with reference to the drawings. The following respective embodiments are described in detail for better understanding of the scope of the invention, and do not limit the present invention unless otherwise specified. In the drawings used in the following description, for easy understanding of the features of the present invention, there are cases in which the main portions are enlarged for the sake of convenience, and the dimensional ratios of the components are not necessarily the same as the actual case.

First, a series of flows of forming process of a bottle can, which is an example of a can body, will be described.

FIG. 1 is a flowchart illustrating an example of a forming process of a bottle can in steps. FIGS. 2A-2G is a schematic view illustrating a change in the shape of the can body in each process.

The bottle can is forming via a plate material punching step S1, a cupping step (drawing step) S2, a DI step (drawing and ironing step) S3, a trimming step S4, a printing and coating (can outer surface) step S5, a coating (can inner surface) step S6, and a necking step S7 in this order.

In the plate material punching step S1, for example, a rolled material made of an Al alloy material is punched to form a disk-like plate material (blank) W as illustrated in FIG. 2A (a punching process is performed). In the cupping step (drawing step) S2, as illustrated in FIG. 2B, the plate material W is drawn (cupped) in a cupping press and is formed into a cup-like body (can base material) W1. In the DI step (drawing and ironing step) S3, DI machining (re-drawing and ironing) is performed on the cup-like body W1 as illustrated in FIG. 2C by the DI machining apparatus, and the can barrel 11 and the bottom 14 form an integral bottomed cylindrical can body W2.

In the trimming step S4, since the height of the opening end portion 11 a of the can body W2 is not uniform, the opening end portion 11 a is trimmed using a trimming device, and as illustrated in FIG. 2D, the trimmed can body W3 in which the height of the opening end portion 11 a of the can barrel 11 is evenly aligned over the entire circumference is formed.

Thereafter, after the can body W3 is cleaned to remove the lubricating oil and the like, the surface treatment is performed and the drying is performed. Thereafter, as illustrated in FIG. 2E, the printing and coating on the outer surface side 11 b of the can body W3 are performed (printing and coating (can outer surface) step S5), and thereafter, the inner surface side 11 c of the can body W3 is coated (coating (can inner surface) step S6).

Next, a neck portion 12 having a smoothly inclined narrowed shape is formed (necking step S7) on the opening end portion 11 a side of the can barrel 11 using a necking tooling. Further, a thread groove 13 (see FIG. 2G) matching the shape of the cap is formed in the neck portion 12 at the opening end portion of the neck portion 12 using a screw tool (molding tool) (a screw forming step S8). The can forming machine according to this embodiment is a necking apparatus used in the necking step S7 and the screw forming step S8. With such a necking apparatus, a can body (bottle can) 10 having a constricted neck portion 12 is formed on the opening end portion 11 a side of the can barrel 11 (see FIG. 2F).

Thereafter, the can body (bottle can) 10 obtained through each of the steps described above is filled with contents such as a beverage or the like, a cap fitted with the thread groove 13 to cover the opening of the neck portion 12 is attached, and the interior of the can body 10 is sealed.

FIG. 3 is an external perspective view illustrating a can forming machine (necking apparatus) including a can discharge unit. FIG. 4 is an external perspective view illustrating the turntable and its peripheral edge portion. Further, FIG. 5 is an enlarged perspective view illustrating a part of the turntable.

A can forming machine (necking apparatus) 20 is a can forming machine used for the necking step S7 and the screw forming step S8 described above, and includes a 21 having a rotary shaft (not illustrated) or a reciprocating unit (not illustrated), a turntable 23 axially attached to the rotary shaft of the main body 21, and a die table 24 disposed to face the turntable 23. Further, a sliding ring member 25 and a fixing ring member 26 are disposed to the vicinity of the turntable 23 in the central direction.

The turntable 23 is, for example, a member in which multiple can body holders 31 capable of holding the bottom portion of the can body are annularly disposed on one surface side 23 a of the table main body (base) 23A having a ring-shaped flat plate. The turntable 23 is rotatably supported by an index (not illustrated) disposed to the main body 21, and intermittently rotates about the rotary axis. The configuration of the can body holder 31 will be described later in detail.

Through air supply grooves and air supply pipes (not illustrated) disposed to each of the sliding ring member 25 and the fixing ring member 26, the gas pressure can be applied to the can body holding unit 33 (see FIG. 7) of the can body holder 31 to be described later via the sliding ring member 25 rotating with the turntable 23.

The die table 24 is, for example, a member in which multiple forming toolings 41 are annularly arranged on one surface side 24 a facing the turntable 23 of the table main body 24A having a ring-shaped flat plate. The die table 24 is disposed to be movable along the X-axis which is the forming direction by a reciprocating unit (not illustrated). That is, the die table 24 reciprocates to narrow or widen the space between the die table 24 and the turntable 23. Further, the turntable 23 only reciprocates along the X-axis without rotating.

The forming tooling 41 includes multiple forming toolings 41, 41 . . . in which the forming shapes are changed in steps in the can body holder 31 of the turntable 23 such that the neck portion 12 (see FIGS. 2A-2G) of the can body 10 is gradually formed from a position opposed to a can body insertion position P1 (see FIG. 6), for example, at which the neck portion pushes an unformed can body, in the rotational direction (counterclockwise direction Q in FIG. 6) of the turntable 23. Further, a screw tool (forming tooling) 61 for forming the thread groove 13 (see FIG. 2G) may be disposed to the opening end narrowed by the neck portion 12, following the forming tooling 41 at the final stage.

FIG. 6 is a plan view of the turntable when viewed from the die table side.

The turntable 23 of the present embodiment intermittently rotates in the counterclockwise direction Q. Further, the can body with the unformed neck portion sent from the previous step is pushed into the can body holder 31, which reaches the position adjacent to a star wheel 51A disposed at the outer edge portion of the turntable 23, among the multiple annularly arranged can body holders 31, 31 . . . (the can body insertion position P1).

Further, the can body 10 formed with the held neck portion 12 is pushed out from the can body holder 31 which reaches the position adjacent to the star wheel 51B (the can body discharge position P2). A can body holding unit 33 or a knock-out unit 34, which will be described later, acts on the can body holder 31 located at the can body insertion position P1 and the can body discharge position P2.

FIG. 7 is a partially cutaway perspective view illustrating an example of the can body holder. FIG. 8 is a cross-sectional view illustrating a state in which the can body holder is at the can body discharge position. Further, FIG. 9 is an enlarged perspective view of a main part when the vicinity of the can body insertion position of the turntable is viewed from the back side. Further, FIG. 10 is a partially broken perspective view when the vicinity of the can body discharge position of the turntable is viewed from the front side.

The can forming machine (necking apparatus) 20 includes the can discharge unit 40 of the present invention. The can discharge unit 40 includes: a cylindrical part 32 into which the can body 10 can be inserted; a knocking out piston 45 which is disposed to be movable in a depth direction of the cylindrical part 32 and is provided to be displaceable between a protruding position protruding in the cylindrical part 32 (see FIG. 8) and a recessed position recessed from the cylindrical part 32 (see FIG. 7); and gas valves 56, 56, . . . (piston displacing unit) that are examples of a piston displacing unit 45 which displaces the knocking out piston from the recessed position toward the protruding position, and the gas valves 56, 56, . . . (piston displacing unit) are disposed selectively to one of discharge positions P2 (see FIG. 6) where the can body 10 is discharged from the cylindrical part 32.

The can body holder 31 includes, for example, a cylindrical part 32 which receives a lower portion (a bottom portion) of the trimmed can body W3 illustrated in FIG. 2D, a can body holding unit 33 disposed to the inner circumferential surface 32 a side of the cylindrical part 32, and a knockout unit 34 disposed to the bottom surface 32 b side of the cylindrical part 32. The opening 32 h, through which the knocking out piston 45 constituting the knockout unit 34 penetrates, is formed on the bottom surface 32 b of the cylindrical part 32.

The can body holding unit 33 includes an elastic part 42 that is partially exposed on the inner circumferential surface 32 a of the cylindrical part 32. The elastic part 42 is, for example, a ring-shaped member having a rectangular cross section made of an elastic member such as rubber and having a hollow portion 42 a formed therein. In the elastic part 42, a first gas pressure adjusting unit 43 for applying the gas pressure from the outside to the inside of the hollow portion 42 a is connected to the sliding ring member 25 and the fixing ring member 26 via the air supply pipe 35.

The first gas pressure adjusting unit 43 is made up of, for example, a compressor which applies the compressed air to the inside of the hollow portion 42 a of the elastic part 42. The operation of the first gas pressure adjusting unit 43 is controlled in accordance with the position of the can body holder 31 disposed to the turntable 23. The opening and closing control of the supply of the gas from the first gas pressure adjusting unit 43 to the elastic part 42 is performed by a change in the relative rotational position between the sliding ring member 25 and the fixing ring member 26.

As illustrated in FIG. 11A, in the can body holding unit 33, in a state in which the gas pressure is not applied from the first gas pressure adjusting unit 43 (see FIG. 7) to the inside of the hollow portion 42 a of the elastic part 42, the elastic part 42 maintains its original shape. In this state, since the elastic part 42 does not protrude from the inner circumferential surface 32 a of the cylindrical part 32, the elastic part 42 does not abut against the circumferential surface of the can body W3. A state illustrated in FIG. 11A is a can body release position at which the can body 10 introduced into the cylindrical part 32 is not locked (held) to the can body holding unit 33.

Meanwhile, as illustrated in FIG. 11B, in a state in which the gas pressure is applied from the first gas pressure adjusting unit 43 (see FIG. 8) to the inside of the hollow portion 42 a of the elastic part 42, the gas pressure inside the hollow portion 42 a of the elastic part 42 increases. As a result, a portion of the elastic part 42 exposed to the inner circumferential surface 32 a of the cylindrical part 32 protrudes (bulges) from the inner circumferential surface 32 a, and narrows the diameter of the inner circumferential surface 32 a of the cylindrical part 32. In this state, the protruding portion 42 b of the elastic part 42 comes into contact with the circumferential surface of the bottom portion of the can body W3, and the can body W3 is held by the bulging elastic part 42. The state illustrated in FIG. 11B is a can body holding position at which the can body 10 introduced into the cylindrical part 32 is engaged (held) with the can body holding unit 33.

The knockout unit 34 includes a knockout cylinder (cylinder) 44, and a knocking out piston 45 supported inside the knockout cylinder 44 to be movable in the X-direction in FIG. 7. The knockout cylinder 44 has a substantially cylindrical cylinder space S. Further, a pressure adjusting hole (gas vent hole) 58 is disposed to the knockout cylinder (cylinder) 44 to release the air compressed in the knockout cylinder 44 by the movement of the knocking out piston 45. The pressure adjusting hole 58 may be, for example, a through-hole which allows the interior and the exterior of the knockout cylinder 44 to communicate with each other. In addition, the knocking out piston 45 is configured to be insertable to and removable from the inside of the cylindrical part 32 through the opening 32 h formed on the bottom surface 32 b of the cylindrical part 32.

An opening 54 through which one surface side 23 a and the other surface side 23 b of the table main body (base) 23A communicate with each other is formed at a position at which the can body holder 31 is disposed in the table main body (base) 23A of the turntable 23. The opening 54 communicates with the cylinder space S formed in the knock-out cylinder 44, such that a gas pressure of a gas such as compressed air can be applied to the inside of the cylinder space S from the other surface side 23 b of the table main body (base) 23A.

Further, on the other surface side 23 b of the table main body (base) 23A, in a portion in which the opening 54 is formed, multiple rectangular spacer plates 55 rotating together with the turntable 23 are disposed lined up. In each of these spacer plates 55, an opening 54 a communicating with the opening 54 formed in the table main body (base) 23A is formed.

On the other surface side 23 b of the table main body (base) 23A constituting the turntable 23, a disk-shaped fixed support plate 57 is further disposed. The fixed support plate 57 is a non-rotatable fixing member, and for example, is disposed to the other surface side 23 b of the table main body (base) 23A to be rotatable with respect to the table main body (base) 23A via the spacer plate 55 to allow rotation of the turntable 23.

Gas valves (piston displacing units) 56, 56, . . . constituting the piston displacing unit are disposed to the fixed support plate 57, from a part corresponding to (overlapping) the can body discharge position P2 (see FIG. 6) for discharging the formed can body 10 from the can body holder 31, to the position corresponding to (overlapping) the can body insertion position P1 (see FIG. 6) along the rotational direction Q of the turntable 23. In the present embodiment, the gas valves (piston displacing units) 56, 56 . . . are disposed to each of positions corresponding to (overlapping) three positions of the can body discharge position P2, the can body insertion position P1, and the position therebetween in the fixed support plate 57 (see FIG. 9).

Meanwhile, the gas valve (piston displacing unit) 56 is disposed between the position subsequent to the can body insertion position P1 (see FIG. 6) along the rotational direction Q of the turntable 23 and the front position of the can body discharge position P2. That is, the gas valve (piston displacing unit) 56 is not disposed to a position facing the position at which the forming tooling 41 and the screw tool 61 are disposed on the die table 24 (the position facing the position at which the forming tooling 41 and the screw tool 61 are disposed on the die table 24 is free of the gas valve (piston displacing unit)).

The gas valve (piston displacing unit) 56 includes a valve main body 60, a connecting pipe 62 disposed to one end side of the valve main body 60, an inner body 64, and a mounting member 65.

The inner body 64 is supported inside the valve main body 60, and a pressure inner tube 63 is disposed thereto. One end side of the pressure inner tube 63 is connected to the connecting pipe 62, and the other end side thereof is exposed as an opening end in the opening 54 formed in the fixed support plate 57. The mounting member 65 locks the gas valve (piston displacing unit) 56 at a position which overlaps the opening 54 formed in the fixed support plate 57.

The connecting pipe 62 of the gas valve (piston displacing unit) 56 communicates with the second gas pressure adjusting unit (gas pressure adjusting unit) 46. The second gas pressure adjusting unit 46 includes, for example, a compressor for feeding the compressed air, a pump for suctioning air, and the like. As a result, the internal pressure of the cylinder space S formed in the knockout cylinder 44 is controlled by the second gas pressure adjusting unit 46 via the gas valve (piston displacing unit) 56.

The gas valve (piston displacing unit) 56 causes the second gas pressure adjusting unit (gas pressure adjusting unit) 46 and the cylinder space S of the knockout cylinder 44 (gas pressure adjusting unit) to communicate with each other via the opening 54 formed in the table main body (base) 23A of the turntable 23. Therefore, the gas pressure of the cylinder space S is enhanced by the operation of the second gas pressure adjusting unit 46, or the internal air is suctioned.

For example, when the compressed air is supplied from the second gas pressure adjusting unit (gas pressure adjusting unit) 46, the gas pressure is applied to the cylinder space S of the knockout cylinder 44 from the gas valve (piston displacing unit) 56 via the opening 54 of the table main body (base) 23A. Thus, for example, when the knocking out piston 45 is at the recessed position (see FIG. 7), the knocking out piston 45 movably supported by the knockout cylinder 44 is displaced to the protruding position (see FIG. 8) by the rise in the internal pressure of the cylinder space S.

The location of the recessed position of the knocking out piston 45 is set to the position where the front end part of the knocking out piston 45 is located in the almost the same location as the bottom surface 32 b of the cylindrical part 32 in the present embodiment. However, alternatively, the location of the recessed position of the knocking out piston 45 may be set to a location where the front end part of the knocking out piston 45 is completely escaped from the cylindrical part 32, for example. In addition, the recessed position may be set to a location where the front end part of the knocking out piston 45 protrudes from the bottom surface 32 b of the cylindrical part 32 within a range in which the can body 10 can be inserted to a predetermined can body holding position without the can bottom 14 abutting to the front end part of the knocking out piston 45 during inserting the can body 10 in the cylindrical part 32.

In addition, the protruding position of the knocking out piston 45 may be set within the range where the knocking out piston 45 protrudes to the location in which the front end part of the knocking out piston 45 contacts the can bottom 14 of the can body 10 and the can body 10 is completely escaped from the cylindrical part 32.

Further, for example, when the suction is performed by the second gas pressure adjusting unit (gas pressure adjusting unit) 46, the cylinder space S of the knockout cylinder 44 is suctioned from the gas valve (piston displacing unit) 56 via the opening 54 of the table main body (base) 23A. Accordingly, when the knocking out piston 45 is at the protruding position (see FIG. 8), the knocking out piston 45 movably supported by the knockout cylinder 44 is displaced to the recessed position (see FIG. 7) by depressurization of the cylinder space S.

A predetermined gap is formed in the spacer plate 55 in a region of the fixed support plate 57 other than the position at which the gas valve (piston displacing unit) 56 is attached, and the interior of the cylinder space S is set to the atmospheric pressure state via the opening 55 a of the spacer plate 55 and the opening 54 of the table main body (base) 23A.

The operation of the can forming machine 20 of the present embodiment having the above configuration will be described.

When the opening side of the can body W3 (see FIG. E) formed in the previous step is drawn, for example, by the can forming machine (necking apparatus) 20 to form the can body 10 (see FIG. 2F) having the neck part 12, for example, the can body with the bottom portion drawn in the previous process is inserted into the cylindrical part 32 of the can body holder 31 at the can body insertion position P1 (see FIG. 6).

When the can body is inserted, the can body holder 31 at the can body insertion position P1 enters the recessed position at which the cylinder space S of the knockout cylinder 44 is suctioned by the second gas pressure adjusting unit 46, and thus, the knocking out piston 45 exits the interior of the cylindrical part 32. The elastic part 42 constituting the can body holding unit 33 enters a state in which no gas pressure is applied from the first gas pressure adjusting unit 43, and is located at the can body release position at which the elastic part 42 does not protrude from the inner circumferential surface 32 a of the cylindrical part 32 (see FIG. 11A).

Further, when the can body 10 is inserted into the cylindrical part 32 of the can body holder 31, the gas pressure is applied from the first gas pressure adjusting unit 43 to the inside of the hollow portion 42 a of the elastic part 42, and the gas pressure inside the hollow portion 42 a of the elastic part 42 increases. As a result, a portion of the elastic part 42 exposed to the inner circumferential surface 32 a of the cylindrical part 32 protrudes (bulges) from the inner circumferential surface 32 a. Further, the can body holding unit 33 at the can body release position is displaced to a can body holding position (see FIG. 11B) at which the elastic part 42 narrows the diameter of the inner circumferential surface 32 a of the cylindrical part 32. As a result, the circumferential surface of the can body W3 introduced into the cylindrical part 32 is clamped by the protruding portion 42 b of the elastic part 42.

Before insertion of the can body W3, the cylinder space S of the knockout cylinder 44 is suctioned in advance by the second gas pressure adjusting unit 46, for example, a suction pump. As a result, the knocking out piston 45 is brought to the recessed position at which it exits the cylindrical part 32.

Further, the knocking out piston 45 is located at the protruding position at the can body discharge position P2 before reaching the can body insertion position P1, and in a state in which the knocking out piston 45 is located at the protruding position, the knocking out piston 45 can also be pushed into the recessed position by a pressing force such as oil pressure for inserting the can body W3 into the can body holder 31 at the can body insertion position P1. In this case, it is possible to omit the suction function from the second gas pressure adjusting unit 46. When the knocking out piston 45 is configured to be pushed into the recessed position by the pressing force for pushing the can body W3 into the can body holder 31, at the can body insertion position P1, the interior of the cylinder space S may be released to the atmosphere.

Thereafter, by the intermittent rotation of the turntable 23, the opening end side of the can body 10 supported by the can body holder 31 is successively pressed against the forming toolings 41, 41 . . . annularly arranged on the die table 24 and is drawn in steps. As a result, while the turntable 23 rotates once, the neck portion 12 (see FIG. 2F) is formed in the can body 10.

During the machining of the can body W3 using the forming toolings 41, 41 . . . and the screw tool 61 (before the can body holder 31 reaches the can body discharge position P2 from the can body insertion position P1), the can body 10 introduced into the cylindrical part 32 of the can body holding unit 33 is held (locked) on the circumferential surface of the bottom portion by the elastic part 42 of the can body holding unit 33.

Further, during machining of the can body W3 using the forming toolings 41, 41 . . . and the screw tool 61, the gas valve (piston displacing unit) 56 connected to the second gas pressure adjusting unit 46 for changing the internal pressure in the cylinder space S is not disposed in the opening 54 formed in the table main body (base) 23A which exposes the rear end side of the knockout cylinder 44 to the outside. Accordingly, it is possible to prevent a problem in which the internal pressure of the cylinder space S increases due to air leakage or the like, the knocking out piston 45 protrudes at an unexpected timing, and the can body being machined falls.

When the can body holder 31 for holding the can body 10 in which the machining of the neck portion 12 using the series of forming toolings 41, 41 . . . and the screw tool 61 or the formation of the thread groove 13 is completed reaches the can body discharge position P2, the can body holding unit 33 stops application of the gas pressure from the first gas pressure adjusting unit 43 (see FIG. 7) toward the elastic part 42. The control of the gas pressure applied to the elastic part 42 is performed by a change in the relative rotational position between the sliding ring member 25 and the fixing ring member 26. Because a state in which the gas pressure is not applied to the elastic part 42 is set, the elastic part 42 returns to the original shape that does not protrude from the inner circumferential surface 32 a of the cylindrical part 32, and is displaced to the can release position at which the can body 10 is not clamped (see FIG. 11A).

Further, the gas pressure is applied from the second gas pressure adjusting unit (gas pressure adjusting unit) 46 to the inside of the cylinder space S of the knockout cylinder 44 via the gas valve (piston displacing unit) 56. Therefore, for example, when the knocking out piston 45 is at the recessed position (see FIG. 7), the knocking out piston 45 movably supported by the knockout cylinder 44 is displaced to the protruding position (see FIG. 8) by the rise in the internal pressure of the cylinder space S.

As a result, the machined can body 10 is discharged from the cylindrical part 32 of the can body holder 31 and is sent to the next process.

After the can body 10 is discharged from the can body holder 31, at any position of the can body insertion position P1 from the can body discharge position P2, the interior of the cylinder space S of the knockout cylinder 44 is suctioned from the second gas pressure adjusting unit (gas pressure adjusting unit) 46 via a gas valve (piston displacing unit) 56. As a result, the knocking out piston 45 movably supported by the knockout cylinder 44 is displaced to the recessed position (see FIG. 7) by depression of the cylinder space S.

As described above, in the can forming machine 20 of the present embodiment, the gas valve (piston displacing unit) 56 for operating the knocking out piston 45 is provided only between the position at which the can body is discharged from the can body holder 31 and the inserting position of the can body. Accordingly, it is possible to reliably prevent an erroneous operation in which the knocking out piston 45 unexpectedly protrudes into the cylindrical part 32 during machining of the can body and causes the can body being machined to fall.

Although embodiments of the present invention have been described above, these embodiments have been presented as examples and are not intended to limit the scope of the invention. These embodiments can be provided in various other forms, and various omissions, substitutions, and changes can be made within a scope that does not depart from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

For example, in the aforementioned embodiment, the knocking out piston is operated by increasing or suctioning the gas pressure in the cylinder space. However, in addition, for example, the knocking out piston may be operated directly by a mechanical operating device such as a cam unit or a spring unit. In addition, an electromagnetic movement unit such as the solenoid may be used.

Further, for example, in the above-described embodiment, as the plurality of forming toolings 41 arranged in the die table 24, an example of a die for forming a neck portion constricted on the opening end side of the can body is adopted. However, the forming tooling is not limited thereto, and a die that gives an arbitrary shape to the can body may be adopted. Further, it is possible to dispose an optional can body machining unit such as a screw machining unit for attaching a bottle cap.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

REFERENCE SIGNS LIST

-   -   10: Can body     -   20: Can forming machine (Necking work apparatus)     -   21: Main body     -   23: Turntable     -   24: Die table     -   31: Can body holder     -   32: Cylindrical part     -   33: Can body holding unit     -   34: Knockout unit     -   40: Can discharge unit     -   41: Forming tooling     -   42: Elastic part     -   43: First gas pressure adjusting unit     -   44: Knockout cylinder (cylinder)     -   45: Knocking out piston     -   46: Second gas pressure adjusting unit     -   56: Gas valve (piston displacing unit)     -   57: Fixed support plate 

What is claimed is:
 1. A can discharge unit comprising: a cylindrical part into which a can body can be inserted; a knocking out piston which is disposed to be movable in a depth direction of the cylindrical part and is provided to be displaceable between a protruding position and a recessed position; and a piston displacing unit which displaces the knocking out piston from the recessed position toward the protruding position, wherein the piston displacing unit is disposed selectively to a discharge position where the can body is discharged from the cylindrical part.
 2. A can forming machine comprising: a turntable in which a plurality of can body holders configured to detachably hold a can body are annularly arranged on one surface side of a base in a disc shape, wherein the can body holders have a cylindrical part into which a bottom side of the can body can be inserted, and a knockout unit, the knockout unit has a knocking out piston which is disposed to be movable in a depth direction of the cylindrical part and is provided to be displaceable between a protruding position at which the knocking out piston protrudes into the cylindrical part and a recessed position at which the knocking out piston exits the cylindrical part, and a cylinder which supports the knocking out piston to be displaceable, and at a discharge position at which the formed can body is discharged from the cylindrical part of the can body holders, a piston displacing unit which displaces the knocking out piston from the recessed position toward the protruding position is provided adjacent to the other surface side of the base.
 3. The can forming machine according to claim 2, wherein an opening through which one surface side and the other surface side of the base communicate with each other is formed in a part of the base in which the can body holders are disposed.
 4. The can forming machine according to claim 2, wherein the piston displacing unit is a gas valve connected to a gas pressure adjusting unit which feeds gas into the cylinder.
 5. The can forming machine according to claim 3, wherein the piston displacing unit is a gas valve connected to a gas pressure adjusting unit which feeds gas into the cylinder.
 6. The can forming machine according to claim 4, wherein the gas valve is further disposed to one or more positions between a position subsequent to the discharge position to an introduction position along a rotational direction of the turntable, and is not disposed between the position subsequent to the introduction position and a position previous to the discharge position.
 7. The can forming machine according to claim 5, wherein the gas valve is further disposed to one or more positions between a position subsequent to the discharge position to an introduction position along a rotational direction of the turntable, and is not disposed between the position subsequent to the introduction position and a position previous to the discharge position.
 8. The can forming machine according to claim 4, wherein the gas valve is disposed to each position between the discharge position and an introduction position at which the can body before forming is introduced into the cylindrical part, and the gas pressure adjusting unit feeds gas into the cylinder via the gas valve and suctions the interior of the cylinder to displace the knocking out piston from the protruding position toward the recessed position.
 9. The can forming machine according to claim 5, wherein the gas valve is disposed to each position between the discharge position and an introduction position at which the can body before forming is introduced into the cylindrical part, and the gas pressure adjusting unit feeds gas into the cylinder via the gas valve and suctions the interior of the cylinder to displace the knocking out piston from the protruding position toward the recessed position.
 10. The can forming machine according to claim 6, wherein the gas valve is disposed to each position between the discharge position and an introduction position at which the can body before forming is introduced into the cylindrical part, and the gas pressure adjusting unit feeds gas into the cylinder via the gas valve and suctions the interior of the cylinder to displace the knocking out piston from the protruding position toward the recessed position.
 11. The can forming machine according to claim 7, wherein the gas valve is disposed to each position between the discharge position and an introduction position at which the can body before forming is introduced into the cylindrical part, and the gas pressure adjusting unit feeds gas into the cylinder via the gas valve and suctions the interior of the cylinder to displace the knocking out piston from the protruding position toward the recessed position.
 12. A can body holder comprising: a cylindrical part which receives a lower portion of a can body; a can body holding unit disposed to an inner circumferential surface side of the cylindrical part; and a knockout unit disposed to a bottom surface side of the cylindrical part, wherein the can body holding unit comprises an elastic part partially exposed on the inner circumferential surface of the cylindrical part, and the knockout unit comprises a knockout cylinder, and a knocking out piston supported inside the knockout cylinder to be movable in an axis direction of the knockout cylinder.
 13. The can body holder according to claim 12, wherein the elastic part is in a ring shape having a rectangular cross section, made of rubber, a hollow portion is formed in the rectangular cross section, and a first gas pressure adjusting unit configured to apply a gas pressure from outside to an inside of the hollow portion is connected to the elastic part.
 14. The can body holder according to claim 12, wherein a substantially cylindrical cylinder shape is formed in the knockout cylinder, a pressure adjusting hole is disposed to the knockout cylinder to release an air compressed in the knockout cylinder by movement of the knocking out piston.
 15. The can body holder according to claim 13 wherein a substantially cylindrical cylinder shape is formed in the knockout cylinder, a pressure adjusting hole is disposed to the knockout cylinder to release an air compressed in the knockout cylinder by movement of the knocking out piston. 